Are you able to filter the file that gets created from Tapin ?
Yes, the Stations can be filtered in Tapin Radio by:
1) Region/Continent /Subcontinent/Country/ Network; single stations
2) Genre/ Country;
3) Network.
There is a nice and efficient Search box in Tapin that allows to group the results as well.
You can use the search function in Notepad ++ to filter the presets.xml file content.
There is an example excerpt from the file:
<Group title="Europe"> - Region/Continent; Subcontinent is applied to America only
<Group title="Poland"> - Country
<Group title="Polskie Radio"> - Network
<Group title="Global"> - Genre
<Station title="1 - Jedynka" url="http://www.polskieradio.pl/jedynka/" genre="News/Features">
<Source>http://www.polskieradio.pl/st/program1M.asx</Source>
</Station>
What about using this Groups as Categories in MB and allow to import the selected group of Radio Stations only
EDIT:
Updated the first hierarchy to include Networks that are grouped before independent stations from the country.